The present invention relates to agricultural implements and, in particular, the present invention relates to towable folding wheel rakes useful to form windrows from cut forage and most particularly to extension linkage useful in towable folding wheel rakes.
For many years it has been a typical agricultural process to cut forage, allow some drying to occur, rake it into piles where some additional drying occurs, collect and store it at a desirable moisture content, and subsequently feed such stored, dried forage to livestock. Weather conditions between the time of cutting and collecting play a major role in determining the resulting quality of the product of this agricultural process. In modern times, as farms have grown dramatically in area and the work force reduced in number, the process has been altered to employ power equipment to rake the drying cut forage into long, continuous windrows, which also encourages drying. The windrows may or may not be formed into bales prior to collection. Weather continues to be a major determinant of the overall outcome and the capability to rapidly rake a large field area in a short time is often critical.
Most modern power equipment for raking cut forage employs rotating tined wheels and most particularly banks of rotating tined wheels which are moved through a field of cut forage to form windrows. These banks of wheel rakes and more importantly multiple banks of wheel rakes can be quite wide to reduce both the time and pathway required to rake a field. Wide rakes thereby offer a potential time and cost savings to agriculture and enhance the opportunity to perform the raking process so as to best utilize favorable weather conditions.
In designing agricultural implements, such as wide hay rakes, relatively minimal frame members sizes are preferred over massive frame members to avoid increased manufacturing cost and increased implement weight. A more expensive implement which requires more fuel input to a larger tow vehicle for operation due to increased weight would sacrifice some of the potential efficiency of wide rakes.
An additional engineering challenge concerns the transport wide rakes between fields. In response to the transport challenge, wide rakes which fold to facilitate transport over highways and through fence gates have become popular in recent years. Peeters in U.S. Pat. Nos. 5,199,252 and 5,305,509 discloses an exemplary folding hay rake. The Peeters rake involves a towable primary transport frame with right and left secondary frames, each having a bank of wheel rakes, pivotally deployed from the rear end of the primary frame by action of a telescoping extension assembly.
Practical and economical pivoting of the secondary frames relative to the primary frame can represent a considerable engineering challenge. The telescoping extension approach of Peeters requires either a very long hydraulic cylinder and ram attached well away from the pivot connection between the primary and secondary frames, or in the alternative, a short, very powerful cylinder and ram, situated close to the pivot connection between the primary and secondary frame.
Each of these two telescopic deployment approaches have certain disadvantages. A long hydraulic cylinder and ram are subject to vibration which might damage relatively thin hydraulic components. Therefore, long hydraulic components must be of a sufficient diameter, often greater than required for mere deployment, in order to withstand the jarring and shock encountered in raking a hay field. Such long and large hydraulic units tend to be relatively heavy and expensive, both undesirable qualities in a folding hay rake. Even short, powerful hydraulic units, mounted near the frame pivot, require heavy mounts and heavier, more massive primary and secondary frames to transmit the hydraulically imparted motion to the end of the secondary frame and its supporting caster wheel. Again, this solution tends away from the desirable objectives of light weight and low capital cost for a folding hay rake.
The present invention provides an ingenious solution to pivotally extending or retracting a secondary frame on a folding wheel rake, while avoiding the above mentioned long or short hydraulic telescopic deployment systems and further incorporating a convenient adjustment of the full extension of the deployment. As in the previously mentioned Peeter's invention entitled Folding Hay Rake, the present invention is compatible with the use of relatively fine frame members on the agricultural implement, which tends to minimize the implement's weight and does not result in excessive increases in manufacturing costs. The agricultural implement of this invention therefore allows even better exploitation of the potential efficiency of a wide folding wheel rake. Further, other aspects of the present invention provide versatility and more precise fine adjustments in forage raking operations.